P0126

Insufficient Coolant Temperature for Stable Operation

Severity

⚠️ Medium

Can you drive?

Limited driving only, diagnose soon

Approx. repair cost

$56–167 (est.)

Symptoms

The engine takes a long time to warm up
Increased fuel consumption
Reduced efficiency of the interior heating system
Possible errors in the oxygen sensor

Causes

Faulty thermostat (stuck open)
Low coolant level
Coolant temperature sensor malfunction
Problems in the cooling system (leaks, blockages)

How to Fix

Check coolant level
Diagnose the operation of the thermostat (warm up the engine and check the temperature of the pipes)
Check the coolant temperature sensor (resistance, signal)
Replace thermostat if necessary
Check the cooling system for leaks and blockages

Related codes

P0125 P0115 P0116